Minimum-power-tracking for PV-PV differential power processing systems

Differential power processing (DPP) structure present obvious advantages in improving the energy output and overall efficiency of a photovoltaic system under the partial shading conditions. This paper presents a novel minimum-power tracking (MPT) algorithm for the two-stage PV-PV DPP structure, where each PV is implemented with the maximum power point tracking (MPPT) control while the central control is control by the MPT. Considering that the string current determines the power processed through the DPP converters, the DPP converters are specially designed to process minimal power in order to achieve higher efficiency. A simulated model using PSIM shows clearly that this system has the tendency to improve power extraction and could work perfectly under various conditions.